/**authorization code generate class
 * how to use?
 * 1 call generateVerifyCode to generate code first
 * 2 call outputImage to generate code file to disk
 * @author lms 2016.07.06
 */

package ms.core.tool;

import java.awt.Color;  
import java.awt.Font;  
import java.awt.Graphics;  
import java.awt.Graphics2D;
import java.awt.RenderingHints;  
import java.awt.geom.AffineTransform;  
import java.awt.image.BufferedImage;  
import java.io.File;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.OutputStream;  
import java.util.Arrays;  
import java.util.Random;
  
import javax.imageio.ImageIO;  

public class CheckCodeTool{  
    //注:默认生成验证码不包含 1,0,i,o
    public static final String CODE_SEED = "123456789ABCDEFGHJKLMNPQRSTUVWXYZ";  
    private static Random random = new Random();  

    /**
     * use system default font to generate code
     * @param codeLen length of verify code
     * @return code values
     */
    public static String generateCheckCode(int codeLen){  
        return generateCheckCode(codeLen, CODE_SEED);
    }  

    /**
     * use specify code seed to generate code
     * @param codeLen
     * @param sources
     * @return check code
     */
    public static String generateCheckCode(int codeLen, String codeSeed){  
        if(StrTool.isBlank(codeSeed)){
        	codeSeed = CODE_SEED;
        }
        int codesLen = codeSeed.length();
        Random rand = new Random(System.currentTimeMillis());
        StringBuilder verifyCode = new StringBuilder(codeLen);
        for(int i = 0; i < codeLen; i++){
        	char c = codeSeed.charAt(rand.nextInt(codesLen-1));
        	if (rand.nextInt() % 2 ==0) c = Character.toLowerCase(c);
            verifyCode.append(c);
        }
        return verifyCode.toString();  
    }  

    /**
     * to make authorize code to indicate file
     * @param w width
     * @param h height
     * @param codeFile file of code to save in the disk
     * @param code check code value
     */
    public static boolean outputImage(int w, int h, String codeFile, String code){  
        //if null or empty codeFile
    	if(StrTool.isBlank(codeFile)) 
            return false;

    	//if directory not exists and create directory failure
        String path = SysTool.getFilePath(codeFile);
        if (SysTool.dirExists(path, true)!=1)
        	return false;

        boolean ret = false;
        File f = new File(codeFile);
        try{
        	f.createNewFile();  
            FileOutputStream fos = new FileOutputStream(f);  
            outputImage(w, h, fos, code);
            fos.close();
            ret = true;
        } catch(IOException e){
        	Log4j2Tool.error(CheckCodeTool.class, "outputImage:", e);
        }
        f = null;
        return ret;
    }

    /**
     * generate code and out put for stream
     * @param w width of image code
     * @param h height of image code
     * @param os out put stream
     * @param code code value
     */  
    public static void outputImage(int w, int h, OutputStream os, String code){  
        int verifySize = code.length();  
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);  
        Random rand = new Random();  
        Graphics2D g2 = image.createGraphics();  
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);  
        Color[] colors = new Color[5];  
        Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN,  
                Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,  
                Color.PINK, Color.YELLOW };  
        float[] fractions = new float[colors.length];  
        for(int i = 0; i < colors.length; i++){  
            colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];  
            fractions[i] = rand.nextFloat();  
        }  
        Arrays.sort(fractions);  
          
        g2.setColor(Color.GRAY);// set image frame color
        g2.fillRect(0, 0, w, h);  
         
        // set background color
        Color c = getRandColor(200, 250);	//random background color
        //Color c = new Color(255, 255, 255);	//white background color
        g2.setColor(c);			
        g2.fillRect(0, 2, w, h-4);  
          
        //draw interfering line
        //Random random = new Random();  
        g2.setColor(getRandColor(160, 200)); // draw line color
        for (int i = 0; i < 20; i++) {  
            int x = random.nextInt(w - 1);  
            int y = random.nextInt(h - 1);  
            int xl = random.nextInt(6) + 1;  
            int yl = random.nextInt(12) + 1;  
            g2.drawLine(x, y, x + xl + 40, y + yl + 20);  
        }

        //to make hot pixel
        float yawpRate = 0.05f;// hot pixel rate
        int area = (int) (yawpRate * w * h);
        for (int i = 0; i < area; i++) {
            int x = random.nextInt(w);
            int y = random.nextInt(h);
            int rgb = getRandomIntColor();
            image.setRGB(x, y, rgb);
        }

        shear(g2, w, h, c);//twist the image

        g2.setColor(getRandColor(100, 160));  
        int fontSize = h-4;  
        Font font = new Font("Algerian", Font.ITALIC, fontSize);  //Algerian 此字体都是大写
        g2.setFont(font);  
        char[] chars = code.toCharArray();  
        for(int i = 0; i < verifySize; i++){  
            AffineTransform affine = new AffineTransform();  
            affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize/2, h/2);  
            g2.setTransform(affine);  
            g2.drawChars(chars, i, 1, ((w-10) / verifySize) * i + 5, h/2 + fontSize/2 - 10);  
        }  

        g2.dispose();

        try {
			ImageIO.write(image, "jpg", os);
		} catch (IOException e) {
			Log4j2Tool.error(CheckCodeTool.class, "outputImage:", e);
		}
    }

    private static Color getRandColor(int fc, int bc) {  
        if (fc > 255)
            fc = 255;  
        if (bc > 255)
            bc = 255;  
        int r = fc + random.nextInt(bc - fc);  
        int g = fc + random.nextInt(bc - fc);  
        int b = fc + random.nextInt(bc - fc);  
        return new Color(r, g, b);
    }

    private static int getRandomIntColor() {  
        int[] rgb = getRandomRgb();  
        int color = 0;  
        for (int c : rgb) {  
            color = color << 8;  
            color = color | c;  
        }  
        return color;  
    }

    private static int[] getRandomRgb() {  
        int[] rgb = new int[3];
        for (int i = 0; i < 3; i++) {  
            rgb[i] = random.nextInt(255);  
        }
        return rgb;  
    }

    private static void shear(Graphics g, int w1, int h1, Color color) {  
        shearX(g, w1, h1, color);
        shearY(g, w1, h1, color);
    }  
      
    private static void shearX(Graphics g, int w1, int h1, Color color) {  
        int period = random.nextInt(2);  
        boolean borderGap = true;  
        int frames = 1;  
        int phase = random.nextInt(2);  
  
        for (int i = 0; i < h1; i++) {
            double d = (period >> 1) * Math.sin((double) i / (double) period
            		+ (6.2831853071795862D * phase) / frames);  
            g.copyArea(0, i, w1, 1, (int) d, 0);  
            if (borderGap) {  
                g.setColor(color);  
                g.drawLine((int) d, i, 0, i);  
                g.drawLine((int) d + w1, i, w1, i);  
            }  
        }
    }  

    private static void shearY(Graphics g, int w1, int h1, Color color) {
        int period = random.nextInt(40) + 10; // 50;  

        boolean borderGap = true;  
        int frames = 20;  
        int phase = 7;  
        for (int i = 0; i < w1; i++) {  
            double d = (period >> 1) * Math.sin((double) i / (double) period
            		+ (6.2831853071795862D * phase) / frames);  
            g.copyArea(i, 0, 1, h1, 0, (int) d);
            if (borderGap) {
                g.setColor(color);  
                g.drawLine(i, (int) d, i, 0);  
                g.drawLine(i, (int) d + h1, i, h1);  
            }
        }
    }
}  
